Question: Solve for $x$ : $-10 + x = -13$
Explanation: Add $10$ to both sides: $ \begin{eqnarray} \\ -10 + x &=& -13 \\ \\ {+10} && {+10} \end{eqnarray} $ $ \begin{eqnarray} \hphantom{-10 + x} &\hphantom{=}& \hphantom{-13} \\ x &=& -13 {+ 10} \\ \end{eqnarray} $ Simplify. $ x = -3$